Airplanes are sometimes powered by gas turbine engines. In some applications, gas turbine engines incorporated into airplanes can be used to independently provide thrust from pressurized exhaust gasses discharged from the engines themselves. In other applications, gas turbine engines incorporated into airplanes can be used to drive shrouded fans used to provide thrust from discharged air moved through ducts. In still other applications, gas turbine engines incorporated into airplanes can be used to drive unshrouded propellers used to provide thrust from air accelerated by the propellers.
The combination of a gas turbine engine and a propeller used in an airplane is sometimes called a turboprop or a turboprop engine. Turboprops sometimes include a gearbox coupled between the gas turbine engine and the propeller to adjust the speed of the propeller relative to the speed of the gas turbine engine. The packaging of such gas turbine engines, propellers, and optional gearboxes can present packaging and aerodynamic design challenges. Accordingly, there are opportunities to improve these designs over the prior art.